Assessing the ecotoxicological effects of novel cellulose nanocrystalline glitter compared to conventional polyethylene terephthalate glitter: toxicity to springtails (Folsomia candida).

Glitter is a type of microplastic, and thus there is a need to assess its potential impacts on the environment and to assess the potential for non-plastic cellulose nanocrystal structurally colored glitters as safe and sustainable replacements. The ecotoxicity of glitter has been mostly ignored in the research literature, with only a few published studies focusing on aquatic organisms. Therefore, an exposure experiment was conducted to examine the impact of conventional polyethylene terephthalate (PET) glitter as well as untreated and heat-treated cellulose nanocrystal (CNC) based one on the survival, reproduction, and length of Folsomia candida (springtail). Folsomia candida reproduction was reduced by 43% (P= 0.009) after exposure to PET glitter at 1000 mg/kg, while no significant effects were observed on F. candida survival and length. In contrast, there were no significant impacts on F. candida survival, length, or reproduction when exposed to untreated or heat-treated CNC glitter. These results indicate that exposure to PET glitter may impact soil invertebrates at the population level, and that CNC glitter has potential as a biodegradable non-plastic alternative to PET glitter to decrease detrimental effects on soil ecosystems.

Land application of industrial wastes: impacts on soil quality, biota, and human health.

Globally, waste disposal options such as landfill, incineration, and discharge to water, are not preferred long-term solutions due to their social, environmental, political, and economic implications. However, there is potential for increasing the sustainability of industrial processes by considering land application of industrial wastes. Applying waste to land can have beneficial outcomes including reducing waste sent to landfill and providing alternative nutrient sources for agriculture and other primary production. However, there are also potential hazards, including environmental contamination. This article reviewed the literature on industrial waste applications to soils and assessed the associated hazards and benefits. The review investigated wastes in relation to soil characteristics, dynamics between soils and waste constituents, and possible impacts on plants, animals, and humans. The current body of literature demonstrates the potential for the application of industrial waste into agricultural soils. The main challenge for applying industrial wastes to land is the presence of contaminants in some wastes and managing these to enhance positive effects and reduce negative outcomes to within acceptable limits. Examination of the literature also revealed several gaps in the research and opportunities for further investigation: specifically, a lack of long-term experiments and mass balance assessments, variable waste composition, and negative public opinion.

The effects of vehicular emissions on the activity and diversity of the roadside soil microbial community.

Motor vehicles emit a variety of pollutants including metals, petroleum hydrocarbons and polycyclic aromatic hydrocarbons (PAHs). The relationships between metals, petroleum hydrocarbons and PAHs, soil respiration and microbial diversity (fungi and bacteria) were studied using control (n = 3) and roadside soils (n = 27) with different exposure periods to vehicle emissions (2-63 years). Bacterial diversity was found to be higher than control sites (P = 0.002) but was the same across different categories of road age (P = 0.328). Significant (r = -0.49, P = 0.007) contrasting behaviour of fungal and bacterial diversity was reported, with diversity increasing across all road types for bacteria and decreasing across all road types for fungi compared to control soils. Analysis of the bacterial community identified three distinct clusters, separated on age of contamination, suggesting that roadside bacterial communities change over time with pollution from vehicles with the potential development of metal resistant bacteria in roadside soils. In contrast, for fungal communities, a reduction in diversity with time of exposure to roadside vehicle emissions was observed suggesting the potential for reduced ecosystem functionality and soil health in roadside soils. This is the first study in the published literature to include both bacterial and fungal responses from aged roadside soils. The results from this study suggest that normal functionality of soil ecosystem services is being affected in roadside soils, potentially globally.

Review of the interactions between vehicular emitted potentially toxic elements, roadside soils, and associated biota.

Given the large size of the world road network, the land area affected by vehicular emissions is extensive. This review provides the first global picture of the relationships between vehicular emitted potentially toxic elements, roadside soils, and risks to associated biota. The following potentially toxic elements that accumulate in roadside soils have been examined in this review: As, Co, Cr, Cu, Mn, Mo, Ni, Pb, Pd, Pt, Rh, Se, Sb, Sn, Sr, Ti and Zn. The meta-analysis undertaken demonstrated an increase in concentrations of Cd, Pb, Zn, Pt, Pd and Rh in roadside soils compared to the mean global crustal concentrations. Positive correlations between potentially toxic element concentrations in roadside soil, plants, microbes, and animals were observed. Roadside studies have found increased potentially toxic element concentrations in plants and animals with increasing proximity to roads. The mean concentrations of Pb in roadside plants and vertebrates were at values above the World Health Organisation guidelines. Research has shown a range of impacts of potentially toxic elements in roadside soils on microbial activity including decreased litter decomposition, nitrogen fixation, nutrient cycling and enzyme synthesis. However, aside from the impact on microbial communities, there has been little research investigating the impacts of roadside soil elements on the associated biota. Thus, there is a need for research that investigates the toxicity of elements in roadside soils to plants and animals and to investigate the transfer of roadside elements through the food chain, and thus, risks posed to human health and the environment.

Arsenic Concentrations and Dietary Exposure in Rice-Based Infant Food in Australia.

Rice-based products are widely used to feed infants and young children. However, the association of rice-based products and high arsenic (As) concentrations have been investigated in a number of studies, but there is limited information from Australia. Therefore, the purpose of this study was to determine the As concentration and dietary exposure in infant rice milk, cereal, crackers and pasta as well as to investigate the relationship between As concentration and rice content, rice type and product origin. Total arsenic (tAs) concentrations were determined by nitric acid digestion and ICP-MS while inorganic arsenic (iAs) was determined by acid extraction, followed by ICP-MS with an interfaced hydride generation system. Nearly 75% of samples had inorganic As exceeding the EU maximum levels for infants and children (0.1 mg kg-1) and the mean iAs percentage of total reached as high as 84.8%. High tAs concentration was positively correlated with rice content and also related to brown (wholegrain). Estimates of dietary exposure showed that infants consuming large amounts of rice pasta or crackers will have an increased risk of health impact associated with excess intake of As through dietary exposure. Moreover, the current Australian guidelines for As in rice (1 mg kg-1) are above the WHO or EU guideline and therefore, will be less protective of high sensitivity consumers like infants and children.

Probing the effects of different lead compounds on the bioavailability of lead to plants.

Lead (Pb) is an important pollutant and is released into the environment in many forms. Different lead compounds have a variety of solubilities and so may impact on lead bioavailability and toxicity when added to soil. In this experimental study, we investigated the bioavailability of Pb in soil spiked with 300, 900 and 1500 mg/kg of Pb-acetate, PbCl2 and PbO using lettuce and wallaby grass. The concentration of Pb in the shoots of both species from control soils (2-3 mg/kg) was similar to previously reported concentrations in plants grown on uncontaminated soils. The Pb concentrations in the plant shoots increased with Pb concentrations in soil for lettuce (R2 = 0.526, P < 0.001) and wallaby grass (R2 = 0.776, P < 0.001). This study demonstrated that Pb bioavailability in soil was not affected by the type of Pb compound added to the soil for both plant species up to 1500 mg/kg Pb concentrations. Instead, the Pb concentration in the plant was best predicted by the total concentration of lead in the soil, irrespective of the original lead compound added to the soil. This research suggests that the original Pb compounds that contaminated the soil are unlikely to be an important factor in assessing Pb bioavailability, and hence risk, in soils.

Quantifying factors related to urban metal contamination in vegetable garden soils of the west and north of Melbourne, Australia.

Vegetable gardens in cities provide communities with fresh vegetables but also may contribute towards public exposure to metals present in soil from historical pollution. Contamination of some Melbourne garden soils with Pb (range 12.9-773 mg kg-1 in soil) was found with some soils exceeding the Australian human health screening criteria for residential land use of 300 mg kg-1. Cadmium concentrations (0.12-1.04 mg kg-1) were above the ambient background soil concentrations of <1 mg kg-1. Nickel concentrations (7.6-40.5 mg kg-1) and Cr (11.6-49.4 mg kg-1) were within the range of expected ambient background concentrations. Distance from the nearest arterial road, house age and the likely use of lead-based paints were the main factors explaining approximately 75% of soil Pb variability in garden soils. Metal concentrations in garden soils of wooden houses were found to be significantly higher than the garden soil of brick and concrete houses (Pb (p < 0.0001)) and Cd (p < 0.001)). Significant correlations were found between backyard garden soil metal concentration and house age for Pb (R2 = 0.83, p < 0.0001) and Cd (R2 = 0.40, p < 0.0002) and the distance from arterial roads for Pb (R2 = 0.38, p < 0.002), while Cr and Ni are related to soil characteristics cation exchange capacity, organic matter, and pH. Vegetable garden with elevated Pb and Cd had recognizable risk factors such as older, painted structures on adjacent houses and closer proximity to arterial roads with higher frequency traffic.

Metal accumulation in roadside soil in Melbourne, Australia: Effect of road age, traffic density and vehicular speed.

Concentrations of vehicular emitted heavy metals in roadside soils result in long term environmental damage. This study assessed the relationships between traffic characteristics (traffic density, road age and vehicular speed) and roadside soil heavy metals. Significant levels were recorded for Cd (0.06-0.59 mg/kg), Cr (18-29 mg/kg), Cu (4-12 mg/kg), Ni (7-20 mg/kg), Mn (92-599 mg/kg), Pb (16-144 mg/kg) and Zn (10.36-88.75 mg/kg), with Mn concentrations exceeding the Ecological Investigation Level. Significant correlations were found between roadside soil metal concentration and vehicular speed (R = 0.90), road age (R = 0.82) and traffic density (R = 0.68). Recently introduced metals in automotive technology (e.g. Mn and Sb) were higher in younger roads, while the metals present for many years (e.g. Cd, Cu, Pb, Zn) were higher in medium and old age roads confirming the risk of significant metal deposition and soil metal retention in roadside soils.